Some photographic situations require specific color corrections. For example, when shooting daylight film under fluorescent lighting, some magenta correction is needed in order to remove the greenish tint that would otherwise appear. The amount of color correction required is most accurately measured via a color temperature meter. Cokin Color Compensating filters are made of plastic and are available in three secondary colors: Cyan, Magenta, and Yellow. A typical designation for one of these filters is CC30C. The "CC" stands for Color Compensating. The "30" stands for a density of 0.30 and the "C" is for cyan.